Consequences of urbanizing landscapes to reproductive performance of birds in remnant forests Amanda D. Rodewald a,⇑ , Laura J. Kearns a , Daniel P. Shustack b a School of Environment and Natural Resources, The Ohio State University, Columbus, OH 43210, USA b Environmental Studies Department, Massachusetts College of Liberal Arts, 375 Church Street, North Adams, MA 01247, USA article info Article history: Received 8 August 2012 Received in revised form 8 October 2012 Accepted 19 December 2012 Keywords: Brood parasitism Nest predation Nest survival Productivity Urban abstract In contrast to the well-documented changes in avian community structure in urbanizing areas, the demo- graphic consequences of urbanization remain less understood. As such, we examined the extent to which an urbanizing landscape matrix affected avian reproductive performance in forests. From 2001 to 2011, we studied five songbird species in 19 forested sites in Ohio, USA and monitored 4264 natural nests to determine rates of daily nest survival and brood parasitism by brown-headed cowbirds (Molothrus ater). We also tracked the annual number of fledglings produced by color-banded pairs of two focal species, the synanthropic northern cardinal (Cardinalis cardinalis, n = 974 breeding pairs between 2003 and 2011) and the urban-avoiding Acadian flycatcher (Empidonax virescens, n = 350 breeding pairs between 2001 and 2011). Over the 10-year period, neither daily nest survival nor brood parasitism rates in remnant forests were consistently related to the amount of urbanization in the surrounding landscape matrix for focal species, with the sole exception of Acadian flycatcher for which the percentage of nests with brood par- asitism increased with urbanization. Annual reproductive output of cardinals was comparable across the rural–urban gradient, but Acadian flycatchers produced fewer fledglings as urbanization increased. These findings demonstrate that urban-associated patterns of annual reproduction cannot necessarily be inferred from nest survival data alone. Moreover, we show that avian community changes are not the simple consequence of nest predation. Understanding ecological processes that operate within metropol- itan areas is critical if we are to conserve biological diversity on our urbanizing planet. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Understanding ecological processes that operate within cities is critical if we are to conserve biological diversity in a world where 60% of the world’s population is projected to live in metropolitan areas by 2030 (Grimm et al., 2008). From a conservation perspec- tive, one particularly worrisome consequence of burgeoning urban populations is that the footprint of cities will continue to expand and increasingly envelop protected natural areas (Mcdonald et al., 2008; Wade and Theobald, 2010). Protected areas have long served as the cornerstone of conservation (Soule and Terborgh, 1999), but within urbanizing landscapes, protected areas may be ill-equipped to sustain viable populations of many native species (Forman, 2008). Ecologists must evaluate how external pressures from urbanization influence the ecological performance of pro- tected areas within a conservation context (Gaston et al., 2008). Though some consequences of urban development may reflect the well-known consequences of fragmentation (e.g., Forman et al., 1976; Ambuel and Temple, 1983; Blake and Karr, 1987; Rob- inson et al., 1995), others result squarely from land use changes within the landscape matrix. Indeed, characteristics of the matrix can alter movement rates (Brown and Kodricbrown, 1977; Gascon et al., 1999; Bender and Fahrig, 2005), provide alternative habitat (Foster and Gaines, 1991; Jules and Shahani, 2003), serve as a source of invaders (Laurance, 1991; Pysek et al., 2002), and deter- mine the severity of edge and area effects (Andren, 1994; Aberg et al., 1995; Donovan et al., 1997). A recent meta-analysis showed that 95% of 104 studies found distinct matrix effects (Prevedello and Vieira, 2010), and, in particular, avian communities may be more sensitive to attributes of the matrix than to area and isolation (Andren, 1994; Kennedy et al., 2010, 2011). Urbanizing landscape matrices are strongly associated with pro- nounced shifts in avian community structure and tend to support fewer Nearctic–Neotropical migratory bird species compared to less developed landscapes (e.g., Mills et al., 1989; Friesen et al., 1995; Rodewald and Bakermans, 2006). Changes in bird communities in human-dominated landscapes have been attributed to concomitant changes in reproductive performance due to patterns of nest preda- tion and/or brood parasitism (Wilcove, 1985; Crooks and Soule, 0006-3207/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.biocon.2012.12.034 ⇑ Corresponding author. Current address: Cornell Lab of Ornithology and Department of Natural Resources, Cornell University, Ithaca, NY 14850, USA (February 2013). Tel.: +1 614 247 6099; fax: +1 614 292 7432. E-mail address: rodewald.1@osu.edu (A.D. Rodewald). Biological Conservation 160 (2013) 32–39 Contents lists available at SciVerse ScienceDirect Biological Conservation journal homepage: www.elsevier.com/locate/biocon